Double-duty 4-wd tractors

The row-crop tractor has long been the primary tractor used on Midwest farms. But an increase in the size of farm implements is stretching the limits of this classic standby.

Take for instance the 36-row Case IH Early Riser planter, which requires a minimum of 270 hp to pull. John Deere’s 48-row DB120 planter, named for its 120-ft. wingspan, takes a recommended 375 engine hp. In comparison, John Deere’s largest row-crop tractor, the 8360R, tops out at 296 PTO hp.

“It would be a real yank with a regular fixed-frame tractor,” says Wade Prouse, marketing manager for New Holland tractors. “Some of the new planters are almost forcing these guys into a four-wheel-drive.”

Prouse says in light of industry’s new large planters and other row-crop implements, farmers need more horsepower and hydraulic capacity than ever before. In response, manufacturers are offering 4-wd models designed with a row-crop chassis capable of running between the rows.

“We can now offer those customers up to 500 engine horsepower in a row-crop package,” Prouse says.

Truck vs. trike

Four-wheel-drive tractors have typically been reserved for “broad-acre” applications such as tillage, scraping, and air seeding, where driving is not limited to the constructs of rows, according to Ryan Shust, marketing manager for Versatile tractors. Shust says, in those applications, horsepower is the main requirement, which 4-wd tractors are designed to deliver. The tractors are built with wider, heavier frames and larger wheels of equal size to transfer up to 600 hp to the ground without spinning or getting stuck.

Row-crop tractors, on the other hand, are designed to provide visibility. Their rigid frame, small front wheels, and narrow chassis allow for tight steering and a clear view of the rows during planting and other row-crop work. But those same features can limit power transfer, says John Bohnker, marketing manager for Case IH row-crop tractors.

“Think of it as a tricycle,” Bohnker explains. “If you load a trike with a 300-hp engine, the wheels are just going to spin, right? It doesn’t have enough weight or footing to transfer the power to the ground. The same thing is true for a tractor. As it grows in horsepower, you have to grow the ability to get that power to the ground by providing enough tire contact and weight to keep the wheels from spinning.”

Hybrid 4-wds

The increased size of farm implements is requiring the benefits of both types of tractors. As a result, more 4-wd models are being offered in wheel spaces that accommodate 30-in. rows.

Case IH and New Holland launched the newest of these “hybrids” last fall. Three 4-wd models in the new Case IH Steiger series and four 4-wd models in New Holland’s T9 series allow tread settings as narrow as 60 in. to accommodate 30-in. row-crop spacing. The new models, which range from 350 to 500 engine hp for New Holland and 350 to 450 engine hp for Case IH, pick up where the largest row-crop tractors leave off.

“It’s basically now a tractor designed for middle U.S.A.,” says New Holland’s Prouse. “Anyone doing row-crop work will find a big benefit because it can now go up and down the rows and offer very high horsepower and up to 113-gal./min. hydraulic flow to handle those heavy draft applications and to pull the largest planters.”

Mitch Kaiser, product manager for Case IH, says the chassis on the tractors was narrowed up to 36 in. instead of the standard 44 in. to allow for 60-in. tread spacing required for row-crop work. In addition, front-wheel frames and fenders were sculpted in to fit 480/95R50 tires, currently industry’s largest tires.

“This 86-in.-tall tire provides a longer footprint within the row than standard radial tires to spread out the weight of the tractor and reduce in-row soil compaction,” Kaiser explains.

Case IH, New Holland, Versatile and Claas all offer 4-wds that can be configured for row crops. AGCO and John Deere offer both track models and 4-wd articulated models with various options to fit row-crop applications (see sidebar).

“We do focus on offering customers a 4-wd row-crop model,” says Dave Guetterman, John Deere. “Every one of our models can be configured for row-crop applications. With the way our chassis is designed, customers can set it up in row-crop configuration pretty easily.”

“Our 4-wds were always used to some degree in row crops,” says Versatile’s Shust. “With the right tire selection they will work in row-crop applications.”

Economical choice

Kaiser says Case IH is seeing a need for “row-crop” Steigers to pull the bigger planters and strip-till rigs. He says, instead of having two or three smaller tractors, a farmer can have one bigger 4-wd and reduce the number of experienced operators required.

Rawly Hicks, marketing manager for AGCO Challenger tractors, reports an increase in demand for 4-wd tractors in the 300- to 400-PTO-hp range. He says this size offers growers an economical choice to the standard row-crop tractors.

“Growers are increasingly conscious of the cost of horsepower,” Hicks says. “As the cost of fixed-frame MFWD technology increases, the power, performance, and maneuverability provided by fully articulated 4-wd machines is available as a more cost-effective choice.”

Place for row-crop tractors

So will the growth in these dual-purpose 4-wds cut into sales of row-crop tractors? Manufacturers say no. All report an increase in sales of both classes.

“You’re right to ask the question,” says Case IH’s Bohnker. “And it would be logical for more of the row-crop tractor demand to go to a Steiger. But there are a lot of farmers who have the mind-set that they want to have a row-crop tractor rather than an articulated tractor.”

In row-crop tractors, steering is tighter and the front wheels track with the direction the driver is turning, he says. Articulated tractors, on the other hand, have a pivot point behind the seat that creates a steering action that is less intuitive.

“Farmers are accustomed to having the steering action where they want it to be,” Bohnker says. “For some people, having both the front tires and rear tires turn on them takes some getting used to.”

Regional differences also are a factor. Bohnker says demand for 4-wds is highest in the Red River Valley and western Canada, where large planters and huge air seeders are common. In other areas like western Iowa, where small fields, point rows, and hills are common, row-crop tractors make more sense because implement size is limited.

“The thing about it is demand for our new 8Rs has been outstanding, too,” adds Guetterman of John Deere. “I would say the numbers are pretty consistent.”

Versatile’s Shust says there will always be good demand for row-crop tractors in applications where rear visibility is important, such as working with a tractor’s PTO or 3-pt. hitch.

“In row-crop tractors you are sitting right over the drawbar, 3-pt. hitch and hydraulic remote valves,” Shust says. “In a large 4-wd, you and your cabin are further away from the implement hook-ups. There will still be requirements for row-crop tractors for reasons like these. But all tractors are going up in horsepower, of course.”